Zero-Common-Mode Modulation of ISOP-Based Dual-Active-Bridge Converter With Power Balance

Abstract

Zero-common-mode (ZCM) modulation, utilizing pulse complementation, is an effective technique for mitigating common-mode (CM) electromagnetic interference (EMI) in multi-module systems. However, its strict pulse timing requirements hinder application in input-series output-parallel (ISOP) dual-active-bridge (DAB) converters. The power and voltage balance between modules can lead to unsynchronized pulse timing, and make it challenging to effectively suppress EMI. In this article, a novel ZCM scheme for ISOP-based DAB is proposed. First, the theoretical relationship between pulse timing and CM voltage is derived, proving ZCM with power balance requires symmetric inductors. Further analysis indicates that among the phase shift modulations, extended phase shift (EPS) modulation is the optimal choice. Finally, a comprehensive design process for the control scheme is proposed. The phase shift ratios of EPS are designed based on zero-voltage switching (ZVS) and active harmonic suppression, to further optimize the CM voltage under ZCM. Theoretical and experimental results validate the feasibility and effectiveness of the proposed scheme.